A significant problem with rechargeable batteries is their general dependency on an external recharging unit, plug and AC socket. This limits the overall “portability” of rechargeable batteries as there is a need to find and carry a charger and connect it to an AC mains supply (which is also less suitable for children due to safety concerns related to high voltages). A further problem is the proliferation of chargers for different battery chemistries creating potential confusion as well as safety concerns, as charging cells in the wrong charger or in an old charger can create problems. Consumers are also inconvenienced by carrying dedicated chargers and cables for each of their appliances. The present arrangements encourage a proliferation of chargers, as well as a disposable battery culture where in excess of 15 billion batteries are thrown away annually, creating a significant environmental and waste problem.
There are now very many USB or other powered ports in existence across a range of computing devices in homes and offices, and on mobile devices, such as laptops, which can act as low voltage power supplies. The mechanisms for USB charging have been well documented and are part of the USB specification. There is an opportunity, as disclosed in our earlier patent applications GB0425967, U.S. Ser. No. 11/211,934, PCT/GB2005/004356, the entire contents of which are hereby incorporated by reference, to create a new battery category of USB Batteries or USB Cells, having in the deployed configuration the same size, format and function as standard format cells so as to fit common appliances and devices, but including circuitry and connectors that can be deployed in a charge mode to enable the device to be charged when connected to a USB port. This application discloses further mechanisms and circuitry to implement advance forms of rechargeable battery assemblies.